State Institution "Institute of Otolaryngology named after Prof. O.S. Kolomiychenko of the NAMS of Ukraine", Kyiv
Introduction. Chemical production is one of the leading industries in Ukraine. Agricultural chemical manufacturing takes a special place in the structure of the chemical industry, owing to the growing need of Ukrainian economy in it, and in a large number of employees. Among various types of enterprises involved in the synthesis of mineral fertilizers or raw materials for their further manufacturing, enterprises of nitrogen-containing and combined fertilizers are of a specific interest from hygienic point of view. This is due to higher toxicity of the initial products as well as a combination of technological processes with formation of toxic ingredients in the production process, including ammonia, nitrogen oxides, carbon monoxide, methanol, formaldehyde.
In the development of chronic laryngitis there is a certain relation on occupational activity of a patient. Vulnerable contingents in the development of this disease are, in particular, voice professionals and chemical workers. Also, there is a problem in diagnostics of pathologies associated with the effect of harmful production factors (HPF) at early stages, when treatment and timely prevention makes it possible to exclude the development of more severe forms of occupational pathologies of the laryngeal apparatus.
The purpose of the study is to analyse a chemical composition of the air of the working zone and hygienic working conditions in production of nitrogen compounds and to study the structure of primary morbidity of the upper respiratory tract in workers.
Materials and methods of research. The parameters of work environment factors (air of the working zone, noise and microclimate) were objects of the study. A hygienic assessment of working conditions (working zone air - 1246 samples, noise level - 45 measurements, microclimate parameters - 60 measurements) at the enterprise “AZOT” was conducted for the following technological processes: production of ammonia, urea, ammonium nitrate and caprolactam. 1246 air samples of toxic substances were taken as a whole. At least three samples were taken at each site.
Also, we have made analysis of the primary morbidity of employees at the enterprise “AZOT” over I-IV quarters of 2018 and assessed pathologies of the upper respiratory tract and ENT organs.
Results. When studying working conditions at the facilities of the PJSC “AZOT” in 2018, we found that ammonia, dioxide and nitric oxide, carbon monoxide, urea, formaldehyde, etc. were main harmful substances. Based on the data obtained, it was revealed that concentrations of ammonia, nitrogen dioxide, oxide carbon exceeded the maximum permissible concentrations (MPC), sometimes by several times. In particular, ammonia content in the urea production workshop was 60.0 mg/m3 (max. value) and 23.8-34.6 mg/m3 (mean values) over the entire process, with a normal value of 20.0 mg/m3. The maximum increase of the nitrogen dioxide concentration in the air of the working zone was 4.5 mg/m3, with the mean values of 1.7-2.8 mg / m3 (MPC <2.0 mg/m3). The concentration of carbon monoxide in the II-III quarters of 2018 exceeded the MPC (<20.0 mg/m3) by 10-15%. As far as for other harmful substances, such as methanol, acrolein, monoethanolamine, formaldehyde, carbamide dust, their concentrations in the air of the manufacturing facilities did not significantly exceed the MPC or were at the limit of the norm.
According to the data of the primary morbidity at the enterprise of production of nitrogen-containing compounds, rather high rates of laryngeal lesions are recorded, accounting for 10.2-12.48% of all primary pathologies of the upper respiratory tract. At the same time, the average morbidity of laryngitis in Cherkasy city in the years of 2013-2017 made 4.1%.
When analysing the structure of the incidence of the upper respiratory tract pathologies for 2018, we revealed a high incidence of tonsillitis, pharyngitis in the cold season and abnormally high incidence of laryngitis and tracheobronchitis in the II-III quarters. As a result of studying the data of the chemical composition of the air of the working zone in quarters I-IV of 2018, the largest exceeding of the MPC for ammonia, nitrogen dioxide, carbon monoxide, ammonium nitrate dust were recorded in quarters II-III. The increase in the incidence of laryngitis and tracheobronchitis in the warm period of the year is likely associated with an increase in the concentration of toxic substances in the air of the working zone and the heating microclimate in production premises in this period.
Conclusions. Working conditions at enterprises of production of nitrogen compounds are characterized by the effect of the combination of unfavourable factors, including high level of the air pollutants in the working zone in combination with the fluctuating microclimate, noise, vibration and intense physical activity. The evaporation of ammonia, nitrogen oxides, carbon monoxide, exceeding the MPC by several times, are priority adverse production factors in production of nitrogen-containing compounds. The average concentrations of air pollutants that exceeded the MPC in the air of the working zone were as follows: ammonia - 23.8-34.6 mg/m3, nitrogen dioxide - 1.7-2.8 mg/m3. The high prevalence of respiratory diseases, especially laryngitis and tracheobronchitis (10.2-12.5%) as compared to the incidence rate for Cherkasy city (4.1%) were found in employees of PJSC “AZOT” producing nitrogen-containing compounds. The high causal probability of the share of a chemical factor (ammonia, nitrous oxides, carbon monoxide, ammonium nitrate dust) in the occurrence of laryngitis, tracheitis, bronchitis among workers of the chemical production of nitrogen-containing compounds is marked.
Key words: chemical industry, diseases of the upper respiratory tract, laryngitis, occupational factors, ammonia, carbon monoxide, nitrogen oxides